Basic Chemistry: Introduction of Chemistry, Atoms and Elements

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Table of Contents

  • Introduction

  • Atoms and Elements

  • Atomic number and atomic mass

  • Periodic Table and Chemical Bonds

  • Isotopes

  • Radioisotopes

  • Electronegativity

  • Chemical Bond

  • Compound, substance, Molecule

  • Acidity and Basicity

  • Redox Reaction

Learning Outcomes

After studying this lesson, you shall be able to:

Introduction of Chemistry


Chemistry is the science of matter, its chemical reactions, composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds.

chemical reactions

Chemical Reactions

  • Chemistry is sometimes called “the central science” because it connects physics with other natural sciences such as geology and biology.

  • Chemistry is a branch of physical science but distinct from physics.

the central science

The Central Science

  • Traditional chemistry starts with the study of elementary particles, atoms, molecules, substances, metals, crystals and other aggregates of matter, in solid, liquid, and gas states, whether in isolation or combination.

  • The reaction and transformations that are studied in chemistry are a result of interaction either between different chemical substances or between matter and energy.

  • Such behaviours are studied in a chemistry laboratory using various forms of laboratory glassware.

Traditional chemistry

Traditional Chemistry

  • A chemical reaction is a transformation of some substances into one or more other substances.

  • It can be symbolically depicted through a chemical equation.

  • The number of atoms on the left and the right in the equation for a chemical transformation is most often equal.

  • The nature of chemical reactions a substance may undergo, and the energy changes that may accompany it are constrained by certain basic rules, known as chemical laws.

  • Energy and entropy considerations are invariably important in almost all chemical studies.

  • Chemical substances are classified in terms of their structure, phase as well as their chemical compositions.

  • They can be analysed using the tools of chemical analysis, e.g. spectroscopy and chromatography.

  • Scientists engaged in chemical research are known as chemists. Most chemists specialize in one or more sub-disciplines.

Energy and entropy considerations

Energy and Entropy Considerations

Atoms and Elements

An atom is the basic unit of chemistry. It consists of a positively charged core (the atomic nucleus) which contains protons and neutrons, and which maintains a number of electrons to balance the positive charge in the nucleus.

Atoms and Elements

Atoms and Elements

The atom is also the smallest entity that can be envisaged to retain the chemical properties of the element, such as electronegativity, ionization potential, preferred oxidation state(s), coordination number, and preferred types of bonds to form (e.g., metallic, ionic, covalent).


1. Chemical reactions can be analyzed by

  1. Spectrometer

  2. Odometer

  3. Tachometer

  4. Speedometer

Answer: A. Spectrometer

2. Scientists engaged in chemical research are known as

  1. Physicist

  2. Biologist

  3. Chemist

  4. Astronomer

Answer: C. Chemist


#atoms and elements

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